ETSI TS V8.5.0 ( ) Technical Specification

Transcription

1 TS V8.5.0 ( ) Technical Specification Universal Mobile Telecommunications System (UMTS); LTE; Policy and charging control over Rx reference point (3GPP TS version Release 8)

2 1 TS V8.5.0 ( ) Reference RTS/TSGC v850 Keywords LTE, UMTS 650 Route des Lucioles F Sophia Antipolis Cedex - FRANCE Tel.: Fax: Siret N NAF 742 C Association à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N 7803/88 Important notice Individual copies of the present document can be downloaded from: The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document Format (PDF). In case of dispute, the reference shall be the printing on printers of the PDF version kept on a specific network drive within Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the current status of this and other documents is available at If you find errors in the present document, please send your comment to one of the following services: Copyright Notification No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute All rights reserved. DECT TM, PLUGTESTS TM, UMTS TM, TIPHON TM, the TIPHON logo and the logo are Trade Marks of registered for the benefit of its Members. 3GPP TM is a Trade Mark of registered for the benefit of its Members and of the 3GPP Organizational Partners. LTE is a Trade Mark of currently being registered for the benefit of its Members and of the 3GPP Organizational Partners. GSM and the GSM logo are Trade Marks registered and owned by the GSM Association.

3 2 TS V8.5.0 ( ) Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to. The information pertaining to these essential IPRs, if any, is publicly available for members and non-members, and can be found in SR : "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to in respect of standards", which is available from the Secretariat. Latest updates are available on the Web server ( Pursuant to the IPR Policy, no investigation, including IPR searches, has been carried out by. No guarantee can be given as to the existence of other IPRs not referenced in SR (or the updates on the Web server) which are, or may be, or may become, essential to the present document. Foreword This Technical Specification (TS) has been produced by 3rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corresponding deliverables. The cross reference between GSM, UMTS, 3GPP and identities can be found under

4 3 TS V8.5.0 ( ) Contents Intellectual Property Rights...2 Foreword...2 Foreword Scope References Definitions and abbreviations Definitions Abbreviations Rx reference point Overview Rx reference model Functional elements AF PCRF PCC procedures over Rx reference point Initial Provisioning of Session Information Modification of Session Information Gate Related Procedures AF Session Termination Subscription to Notification of Signalling Path Status Traffic Plane Events IP-CAN Session Termination Service Data Flow Deactivation Notification of Signalling Path Status IP-CAN type change Notification Access Network Charging Information Notification Rx protocol Protocol support Initialization, maintenance and termination of connection and session Rx specific AVPs Abort-Cause AVP Access-Network-Charging-Address AVP Access-Network-Charging-Identifier AVP Access-Network-Charging-Identifier-Value AVP AF-Application-Identifier AVP AF-Charging-Identifier AVP Codec-Data AVP Flow-Description AVP Flow-Number AVP Flows AVP Flow-Status AVP Flow-Usage AVP Specific-Action AVP Max-Requested-Bandwidth-DL AVP Max-Requested-Bandwidth-UL AVP Media-Component-Description AVP Media-Component-Number AVP Media-Sub-Component AVP Media-Type AVP RR-Bandwidth AVP RS-Bandwidth AVP SIP-Forking-Indication AVP Service-URN AVP...24

5 4 TS V8.5.0 ( ) Acceptable-Service-Info AVP Service-Info-Status-AVP Rx re-used AVPs Use of the Supported-Features AVP on the Rx reference point Rx specific Experimental-Result-Code AVP values Rx messages AA-Request (AAR) command AA-Answer (AAA) command Re-Auth-Request (RAR) command Re-Auth-Answer (RAA) command Session-Termination-Request (STR) command Session-Termination-Answer (STA) command Abort-Session-Request (ASR) command Abort-Session-Answer (ASA) command...29 Annex A (normative): IMS Related P-CSCF Procedures over Rx...30 A.1 Provision of Service Information at P-CSCF...30 A.2 Enabling of IP Flows...31 A.3 Support for SIP forking...31 A.3.1 PCC rule provisioning for early media for forked responses...31 A.3.2 Updating the provisioned PCC rules at the final answer...32 A.4 Notification of AF Signalling Transmission Path Status...32 A.5 Indication of Emergency Session...33 A.6 Notification IP-CAN Type Change...33 Annex B (normative): Flow identifiers: Format definition and examples...34 B.1 Format of a flow identifier...34 B.2 Example B.3 Example B.4 Example 3 without media components...37 B.5 Example Annex C (informative): Limited PCC Deployment...39 C.1 Specific-Action AVP...39 Annex D (informative): Change history...40 History...42

6 5 TS V8.5.0 ( ) Foreword This Technical Specification has been produced by the 3 rd Generation Partnership Project (3GPP). The contents of the present document are subject to continuing work within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for information; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document.

7 6 TS V8.5.0 ( ) 1 Scope The present document provides the stage 3 specification of the Rx reference point for the present release. The functional requirements and the stage 2 specifications of the Rx reference point are contained in 3GPP TS [7]. The Rx reference point lies between the Application Function and the Policy and Charging Rule Function. Whenever it is possible the present document specifies the requirements for the protocol by reference to specifications produced by the IETF within the scope of Diameter. Where this is not possible, extensions to Diameter are defined within the present document. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For a specific reference, subsequent revisions do not apply. For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. [1] 3GPP TR : "Vocabulary for 3GPP Specifications". [2] 3GPP TS : "Policy and Charging Control architecture". [3] void [4] void [5] 3GPP TS : "Policy control over Gq interface", latest Rel-6 version. [6] void [7] 3GPP TS : "Rx Interface and Rx/Gx signalling flows", latest Rel-6 version. [8] 3GPP TS : "Policy and Charging Control over Gx reference point". [9] 3GPP TS : "Policy and Charging Control signalling flows and QoS parameter mapping". [10] IETF RFC 3588: "Diameter Base Protocol". [11] IETF RFC 3556: "Session Description Protocol (SDP) Bandwidth Modifiers for RTP Control Protocol (RTCP) Bandwidth". [12] IETF RFC 4005: "Diameter Network Access Server Application". [13] IETF RFC 4566: "SDP: Session Description Protocol". [14] IETF RFC 4006: "Diameter Credit Control Application". [15] TS : "Telecommunications and Internet Converged Services and Protocols for Advanced Networking (TISPAN); Resource and Admission Control: DIAMETER protocol for session based policy set-up information exchange between the Application Function (AF) and the Service Policy Decision Function (SPDF); Protocol specification". [16] 3GPP TS : "IP Multimedia Subsystem (IMS); Stage 2". [17] 3GPP TS : "IP Multimedia Call Control Protocol based on SIP and SDP; Stage 3".

8 7 TS V8.5.0 ( ) [18] IETF RFC 3264: "An Offer/Answer Model with the Session Description Protocol (SDP)". [19] IETF RFC 4566: "SDP: Session Description Protocol". [20] IETF RFC 3162: "Radius and IPv6". [21] IETF RFC 5031: "A Uniform Resource Name (URN) for Emergency and Other Well-Known Services". [22] 3GPP TS : "Interworking between the Public Land Mobile Network (PLMN) supporting packet based services and Packet Data Networks (PDN)". [23] 3GPP TS : "Telecommunication management; Charging management; Charging architecture and principles". [24] 3GPP TS : "Telecommunication management; Charging management; Diameter charging applications". [25] 3GPP TS : "Cx and Dx interfaces based on the Diameter protocol; Protocol details" [26] 3GPP TS : "IP Multimedia (IM) Core Network (CN) subsystem Centralized Services (ICS); Stage 3". 3 Definitions and abbreviations 3.1 Definitions For the purposes of the present document, the terms and definitions given in 3GPP TR [1] and the following apply: Application Function (AF): element offering application(s) thatguse IP bearer resources NOTE: One example of an AF is the P-CSCF of the IM CN subsystem. AF Session: application level session established by an application level signalling protocol offered by the AF that requires a session set-up with explicit session description before the use of the service. NOTE: One example of an application session is an IMS session. Attribute-Value Pair (AVP): See RFC 3588 [5], corresponds to an Information Element in a Diameter message. binding: PCRF process of associating IP flows described in AF Service Information with IP-CAN bearers. IP-CAN bearer: IP transmission path of defined capacity, delay and bit error rate, etc. See 3GPP TS [1] for the definition of bearer. IP-CAN session: association between a UE and an IP network (for GPRS, APN). The association is identified by one or more UE IP addresses (one IPv4 and/or one IPv6 address) together with a UE identity information, if available, and a PDN represented by a PDN ID (e.g. an APN). An IP-CAN session incorporates one or more IP-CAN bearers. Support for multiple IP-CAN bearers per IP-CAN session is IP-CAN specific. An IP- CAN session exists as long as the related UE IP addresses are assigned and announced to the IP network. IP flow: unidirectional flow of IP packets with the same source IP address and port number and the same destination IP address and port number and the same transport protocol Port numbers are only applicable if used by the transport protocol. packet flow: A specific user data flow carried through the PCEF. A packet flow can be an IP flow. PCC rule: set of information enabling the detection of a service data flow and providing parameters for policy control and/or charging control

9 8 TS V8.5.0 ( ) service information: set of information conveyed from the AF to the PCRF over the Rx interface to be used as a basis for PCC decisions at the PCRF, including information about the AF session (e.g. application identifier, type of media, bandwidth, IP address and port number) service data flow: An aggregate set of packet flows. 3.2 Abbreviations For the purpose of the present document, the abbreviations given in 3GPP TR [1] and the following apply: AF AVP CRF IP-CAN PCC PCEF PCRF PDF P-CSCF QoS SDF SPR UE Application Function Attribute Value Pair Charging Rules Function IP Connectivity Access Network Policy and Charging Control Policy and Charging Enforcement Function Policy and Charging Rule Function Policy Decision Function Proxy-Call Session Control Function Quality of Service Service Data Flow Subscriber Profile Repository User Equipment 4 Rx reference point 4.1 Overview The Rx reference point is used to exchange application level session information between the Policy and Charging Rules Function (PCRF) and the Application Function (AF). As defined in the stage 2 specifications (3GPP TS [2]), this information is part of the input used by the PCRF for the Policy and Charging Control (PCC) decisions. The PCRF exchanges the PCC rules with the Policy and Charging Enforcement Function (PCEF) and QoS rules with the Bearer Binding and Event Reporting Function (BBERF) as specified in 3GPP TS [8]. Signalling flows related to the both Rx and Gx interfaces are specified in 3GPP TS [9]. 4.2 Rx reference model The Rx reference point is defined between the PCRF and the AF. The relationships between the different functional entities involved are depicted in figure 4.1.

10 9 TS V8.5.0 ( ) Application Function (AF) Rx Subscription Profile Repository (SPR) Sp Policy and Charging Rules Function (PCRF) Bearer Binding and Event Reporting Function Gxx Gx Policy and Charging Enforcement Function Gy Online Charging System (OCS) Service Data Flow Based Credit Control (BBERF) (PCEF) AN-Gateway PDN-Gateway Offline Charging System Gz (OFCS) Figure 4.1: Rx reference point at the Policy and Charging Control (PCC) architecture NOTE: The details associated with the Sp reference point are not specified in this Release. The SPR's relation to existing subscriber databases is not specified in this Release. 4.3 Functional elements AF The AF is an element offering applications that require the Policy and Charging Control of traffic plane resources (e.g. UMTS PS domain/gprs domain resources). One example of an application function is the P-CSCF. The AF shall use the Rx reference point to provide session information to the PCRF. NOTE: The AFs may be deployed by the same operator offering the IP-CAN or may be provided by external third party service provider PCRF The PCRF (Policy Control and Charging Rules Function) is a functional element that encompasses policy control decision and flow based charging control functionalities. These 2 functionalities are the heritage of the release 6 logical entities PDF and CRF respectively. The PCRF provides network control regarding the service data flow detection, gating, QoS and flow based charging (except credit management) towards the PCEF. The PCRF receives session and media related information from the AF and informs AF of traffic plane events. The PCRF may check that the service information provided by the AF is consistent with the operator defined policy rules before storing the service information. The service information shall be used to derive the QoS for the service. The

11 10 TS V8.5.0 ( ) PCRF may reject the request received from the AF and as a result the PCRF shall indicate, in the response to the AF, the service information that can be accepted by the PCRF. The PCRF may use the subscription information as basis for the policy and charging control decisions. The subscription information may apply for both session based and non-session based services. The subscription specific information for each service may contain e.g. max QoS class and max bit rate. If the AF requests it, the PCRF shall report IP-CAN session events (including bearer events and events on AF signalling transport) to the AF via the Rx reference point. The PCRF PCC/QoS Rule decisions may be based on one or more of the following: - the session and media related information obtained from the AF via the Rx reference point; - the bearer and subscriber related information obtained from the PCEF over the Gx reference point; - the bearer and subscriber related information obtained from the BBERF over the Gxx reference point; - subscriber and service related data the PCRF may be aware of by configuration or through the Sp reference point; - pre-configured information in the PCRF. NOTE: The details associated with the Sp reference point are not specified in this Release. The SPR's relation to existing subscriber databases is not specified in this Release. The PCRF shall provision PCC/QoS Rules to the PCEF/BBERF via the Gx/Gxx reference point. 4.4 PCC procedures over Rx reference point Initial Provisioning of Session Information When a new AF session is being established and media information for this AF session is available at the AF and the related media require PCC supervision, the AF shall open an Rx Diameter session with the PCRF for the AF session using an AA-Request command. The AF shall provide the UE's IP address using either Framed-IP-Address AVP or Framed-IPv6-Prefix AVP, and the corresponding Service Information within Media-Component-Description AVP(s). The AF shall not include circuit-switched bearer related media in the service information sent to the PCRF. The AF shall indicate to the PCRF as part of the Media-Component-Description whether the media IP flow(s) should be enabled or disabled with the Flow-Status AVP. NOTE: NOTE: The AF does not need to open an Rx Diameter session with the PCRF, if the SDP payload is only proposing to use a circuit-switched bearer (i.e. "c=" line set to "PSTN" and an "m=" line set to "PSTN", refer to 3GPP TS [26]). The Rx Diameter session used for an AF session is different from the Rx Diameter session possibly used for the notifications of the status of the AF signalling transmission path. A new Rx Diameter session is established for each new AF session. The AF may include the AF-Application-Identifier AVP into the AA-Request in order to indicate the particular service that the AF session belongs to. This AVP can be provided at both AF session level, and Media-Component-Description level. When provided at both levels, the AF-Application Identifier provided within the Media-Component-Description AVP will have precedence. The AF may include the AF-Charging-Identifier AVP into the AA-Request for charging correlation purposes. The AF may also include the Specific-Action AVP to request notification for certain user plane events, e.g. bearer termination. The AF may include the Service-URN AVP in order to indicate that the new AF session relates to emergency traffic. If the PCRF receives the Service-URN AVP indicating an emergency session, the PCRF may apply special policies, for instance prioritising service flows relating to the new AF session or allowing these service flows free of charge.

12 11 TS V8.5.0 ( ) If the AF provides service information that has been fully negotiated (e.g. based on the SDP answer), the AF may include the Service-Info-Status AVP set to FINAL_SERVICE_INFORMATION. In this case the PCRF shall authorize the session and provision the corresponding PCC/QoS rules to the PCEF/BBERF. The AF may additionally provide preliminary service information not fully negotiated yet (e.g. based on the SDP offer) at an earlier stage. To do so, the AF shall include the Service-Info-Status AVP with the value set to PRELIMINARY SERVICE INFORMATION. Upon receipt of such preliminary service information, the PCRF shall perform an early authorization check of the service information. For GPRS, the PCRF shall not provision PCC rules towards the PCEF unsolicitedly. However, the PCRF may authorize a PCC/QoS rule request received from the PCEF/BBERF as per 3GPP TS [8]. When the PCRF receives an initial AA-Request from the AF, the PCRF shall perform session binding as described in 3GPP TS [9]. To allow the PCRF to identify the IP-CAN session for which this request applies, the AF shall provide either the Framed-IP-Address or the Framed-IPv6-Prefix containing the routable IP address applicable for the IP Flows towards the UE. In case of private IP address being used, the AF may also provide PDN information if available in the Called-Station-ID AVP for session binding If the PCRF fails in executing session binding, the PCRF responds to the AF with an AA-Answer including the Experimental-Result-Code AVP set to the value IP-CAN_SESSION_NOT_AVAILABLE. Further details on how the PCRF identifies suitable IP-CAN sessions can be found in the binding mechanism described in 3GPP TS [9]. If the request contains Media-Component-Description Attribute-Value Pair(s) (AVP(s)) the PCRF shall store the received Service Information. The PCRF shall process the received Service Information according to the operator policy and may decide whether the request is accepted or not. The PCRF may take the priority information within the Reservation-Priority AVP into account when making this decision. If the service information provided in the AA- Request command is rejected (e.g. the subscribed guaranteed bandwidth for a particular user is exceeded), the PCRF shall indicate in the AA-Answer the cause for the rejection with the Experimental-Result-Code AVP set to the value REQUESTED_SERVICE_NOT_AUTHORIZED. The PCRF may additionally provide the acceptable bandwidth within the Acceptable-Service-Info AVP. To allow the PCRF and PCEF to perform PCC rule authorization and bearer binding for the described service IP flows, the AF shall supply both source and destination IP addresses and port numbers within the Flow-Description AVP, if such information is available. NOTE: In SDP source port information is usually not available. The AF may specify the Reservation-Priority AVP at request level in the AA-Request in order to assign a priority to the AF Session as well as specify the Reservation-Priority AVP at the media-component-description AVP level to assign a priority to the IP flow. The presence of the Reservation-Priority in both levels does not constitute a conflict as they each represent different types of priority. Specifically the Reservation-Priority at the AA-Request level provides the relative priority for a session while the Reservation-Priority at the media-component-description level provides the relative priority for an IP flow within a session. If the Reservation-Priority AVP is not specified the requested priority is DEFAULT (0). The AF may request notifications of specific IP-CAN session events through the usage of the Specific-Action AVP in the AA-Request command. The PCRF shall make sure to inform the AF of the requested notifications in the event that they take place. The PCRF shall check whether the received Service Information requires PCC/QoS Rules to be created and provisioned and/or authorized QoS to be provisioned. Provisioning of PCC/QoS Rules and Authorized QoS to the PCEF/BBERF shall be carried out as specified at 3GPP TS [8]. The PCRF shall reply with an AA-Answer to the AF. The acknowledgement towards the AF should take place before or in parallel with any required PCC Rule provisioning towards the PCEF and shall include the Access-Network- Charging-Identifier(s) and may include the Access-Network-Charging-Address AVP, if they are available. The AA- Answer message shall also include the IP-CAN-Type AVP, if such information is available. In that case, the AA- Answer message shall also include the RAT-Type AVP when applicable for the specific IP-CAN Type (e.g. 3GPP IP- CAN Type). If the PCRF needs to terminate the Rx session before it has sent the AA Answer, the PCRF shall send the AA Answer immediately and before the AS Request.

13 12 TS V8.5.0 ( ) The behaviour when the AF does not receive the AA Answer, or when it arrives after the internal timer waiting for it has expired, or when it arrives with an indication different than DIAMETER_SUCCESS, are outside the scope of this specification and based on operator policy Modification of Session Information The AF may modify the session information at any time (e.g. due to an AF session modification or internal AF trigger) sending an AA-Request command to the PCRF containing the Media-Component-Description AVP(s) with the updated Service Information. If the AF provides service information that has been fully negotiated (e.g. based on the SDP answer), the AF may include the Service-Info-Status AVP set to FINAL_SERVICE_INFORMATION. In this case the PCRF shall authorize the session and provision the corresponding PCC rules to the PCEF. The AF may additionally provide preliminary service information not fully negotiated yet (e.g. based on the SDP offer) at an earlier stage. To do so, the AF shall include the Service-Info-Status AVP with the value set to PRELIMINARY SERVICE INFORMATION. Upon receipt of such preliminary service information, the PCRF shall perform an early authorization check of the service information. For GPRS, the PCRF shall not provision PCC rules towards the PCEF unsolicitedly. However, the PCRF may authorize a PCC/QoS rule request received from the PCEF/BBERF as per 3GPP TS [8]. The PCRF shall process the received Service Information according the operator policy and may decide whether the request is accepted or not. If the updated Service Information is not acceptable (e.g. subscribed guaranteed bandwidth for a particular user is exceeded), the PCRF shall indicate in the AA-Answer the cause for the rejection with the Experimental-Result-Code AVP set to the value REQUESTED_SERVICE_NOT_AUTHORIZED. The PCRF may additionally provide the acceptable bandwidth within the Acceptable-Service-Info AVP. If accepted, the PCRF shall update the Service Information with the new information received. Due to the updated Service Information, the PCRF may need to create, modify or delete the related PCC rules and provide the updated information towards the PCEF following the corresponding procedures specified at 3GPP TS [8]. The procedures to update the Authorized QoS for the affected IP-CAN bearer are also specified at 3GPP TS [8]. The PCRF shall reply with an AA-Answer to the AF. The acknowledgement towards the AF should take place before or in parallel with any required PCC Rule provisioning towards the PCEF and shall include the Access-Network- Charging-Identifier(s) and may include the Access-Network-Charging-Address AVP, if they are available at this moment and have not been yet supplied earlier to the AF. The AA-Answer message shall include the IP-CAN-Type AVP if such information is available and has not yet been supplied earlier to the AF. In that case, the AA-Answer message shall also include the RAT-Type AVP when applicable for the specific IP-CAN Type (e.g. 3GPP IP-CAN Type). If the PCRF needs to terminate the Rx session before it has sent the AA Answer, the PCRF shall send the AA Answer immediately and before the AS Request Gate Related Procedures Depending on the application, in the Service Information provision, the AF may instruct the PCRF when the IP flow(s) are to be enabled or disabled to pass through the IP-CAN. The AF does this by sending the AA-Request message containing the Media-Component- Description AVP(s) that contains the flow status information (in the Flow-Status AVP) for the flows to be enabled or disabled. In response to this action the PCRF shall set the appropriate gate status for the corresponding active PCC rule(s). If a Media-Sub-Component AVP under a Media-Component-Description AVP contains a Flow-Usage AVP with the value RTCP, then the corresponding RTCP IP Flows in both directions shall be enabled even if the Flow-Status AVP under the Media-Sub-Component AVP is set to ENABLED-UPLINK, ENABLED-DOWNLINK, ENABLED, or DISABLED. The PCRF shall reply with an AA-Answer and shall include the Access-Network-Charging-Identifier(s) available at this moment. The PCRF forwards the AF decision to enable or disable the authorized IP flows. The behaviour when the AF does not receive the AAA, or when it arrives after the internal timer waiting for it has expired, or when it arrives with an indication different than DIAMETER_SUCCESS, are outside the scope of this specification and based on operator policy.

14 13 TS V8.5.0 ( ) AF Session Termination When an AF session is terminated, the AF shall send a Session-Termination-Request command to the PCRF. When the PCRF receives a ST-Request from the AF, indicating an AF session termination, it shall acknowledge that request by sending a ST-Answer to the AF. Afterwards, it shall free the resources allocated for the corresponding Service Data Flow(s). In order to do that, the PCRF shall initiate the request for the removal of any related PCC/QoS rules from the PCEF/BBERF and for the update of the Authorized QoS for the affected IP-CAN bearer following the corresponding procedures specified at 3GPP TS [8] Subscription to Notification of Signalling Path Status An AF may subscribe to notifications of the status of the AF Signalling transmission path. To do so, the AF shall open an Rx Diameter session with the PCRF for the AF signalling using an AA-Request command. The AF shall provide the UE's IP address (using either the Framed-IP-Address AVP or the Framed-IPv6-Prefix AVP) and the Specific-Action AVP requesting the subscription to "INDICATION_OF_LOSS_OF BEARER" and/or 'INDICATION_OF_RELEASE_OF_BEARER'. The AF shall additionally provide a Media-Component-Description AVP including a single Media-Sub-Component AVP with the Flow-Usage AVP set to the value "AF_SIGNALLING". The Media-Component-Description AVP shall contain the Media-Component-Number AVP set to '0', and the Media- Sub-Component AVP shall contain the Flow-Number AVP set to '0'. The rest of AVPs within the Media-Component- Description and Media-Sub-Component AVPs shall not be used in this case. When the PCRF receives an AA-Request as described in the preceding paragraph from the AF, the PCRF shall perform session binding as described in 3GPP TS [9] and acknowledges the AAR command by sending an AA-Answer command to the AF. PCC/QoS Rules related to AF Signalling IP Flows should be provisioned to PCEF/BBERF using the corresponding procedures specified at 3GPP TS [8] at an earlier stage (e.g. typically at the establishment of the IP-CAN bearer dedicated for AF Signalling IP Flows). The PCRF may install the corresponding dynamic PCC/QoS rule for the AF signalling IP flows if none has been installed before. The AF may cancel the subscription to notifications of the status of the AF Signalling transmission path at any time. In that case, the AF shall use a Session-Termination-Request (STR) command to the PCRF, which shall be acknowledged with a Session-Termination-Answer (STA) command Traffic Plane Events IP-CAN Session Termination When an IP-CAN session is terminated, the PCRF shall inform the AF about the IP-CAN session termination by sending an ASR (abort session request) command to the AF on each active Rx Diameter session. When the AF receives the ASR command, it shall acknowledge the command by sending an ASA (abort session answer) command to the PCRF and indicate the termination of the session by sending an STR (session termination request) command to the PCRF. The PCRF shall acknowledge the termination of the session by sending an STA (session termination answer) command to the AF. Signalling flows for IP-CAN session termination cases are presented in 3GPP TS [9] Service Data Flow Deactivation It may happen that one or more PCC/QoS Rules (i.e. Service Data Flows) are deactivated at the PCEF/BBERF at a certain time, either permanently or temporarily. When the PCRF gets the knowledge that one or more SDFs have been deactivated, (e.g. due to a bearer release or loss of bearer or out of credit condition), the PCRF shall inform the AF accordingly if the AF has previously subscribed using the Specific-Action AVP in the AAR command. When not all the service data flows within the AF session are affected, the PCRF shall inform the AF by sending an RAR (re-authorization request) command. The RAR command shall include the deactivated IP Flows encoded in the Flows AVP and the cause encoded in the Specific-Action AVP.

15 14 TS V8.5.0 ( ) When the AF receives the RAR command, it shall acknowledge the command by sending an RAA (re-authorization answer) command to the PCRF. The AF may also update the session information by sending an AAR (AA-request) command to the PCRF. If the PCRF receives the AAR command, it shall acknowledge the command by sending an AAA (AA-answer) command to the AF. When all the service data flows within the AF session are affected, the PCRF shall inform the AF by sending an ASR command on the Rx Diameter session related to the AF session. When the AF receives the ASR command, it shall acknowledge the command by sending an ASA (abort session answer) command to the PCRF. After that the AF shall initiate an AF session termination procedure as defined in clause Signalling flows for Service Data Flow Deactivation cases are presented in 3GPP TS [9] Notification of Signalling Path Status In the event that the PCRF is notified of the loss or release of resources associated to the PCC/QoS Rules corresponding with AF Signalling IP Flows, the PCRF shall inform the AF about the Loss of the Signalling Transmission path by sending a Re-Authorization Request (RAR) command to the AF. The RAR shall include the Specific-Action AVP set to the value "INDICATION_OF_LOSS_OF_BEARER" and/or 'INDICATION_OF_RELEASE_OF_BEARER' and the deactivated IP Flow encoded in the Flows AVP. NOTE: If the IMS signalling specific PCC rules include a QCI corresponding to a non-gbr bearer, the INDICATION_OF_LOSS_OF_BEARER will not be reported. When the AF receives the RAR command, it shall acknowledge the command by sending an RAA command to the PCRF. The AF may then decide to terminate the Rx Diameter session used for the notification of the status of the AF Signalling transmission path. The AF may also decide to terminate any other active Rx Diameter session with the PCRF related to the AF Signalling which is not available any longer. In that case, the AF shall then initiate the AF Termination procedure towards the PCRF as defined in clause IP-CAN type change Notification If the AF has successfully subscribed for change notifications in UE's IP-CAN type, then the PCRF shall send a RAR command when a corresponding event occurs in the subscription status i.e change in UE's IP-CAN type. In this case the RAR from the PCRF shall include the Specific-Action AVP for the subscribed event and include the IP-CAN-Type AVP for the UE's new IP-CAN. The RAR command shall additionally include the RAT-Type AVP when applicable for the specific IP-CAN Type (e.g. 3GPP IP-CAN Type) Access Network Charging Information Notification If the AF has subscribed to a notification about Access Network Charging Information and the PCRF obtains new or modified access network charging information from the PCEF, and if there is no unanswered AAR at this point in time, the PCRF shall notify the AF by sending a Re-Authorization Request (RAR) command to the AF. The RAR shall include the Specific-Action AVP set to the value "CHARGING_CORRELATION_EXCHANGE" and and shall include the new of modified Access-Network-Charging-Identifier(s) and may include the Access-Network-Charging-Address AVP. 5 Rx protocol 5.1 Protocol support The Rx interface in the present release is based on Rx and Gq protocols defined for Release 6 as specified in 3GPP TS [7] and 3GPP TS [5] respectively. However, to be able to separate the policy and charging rules function (PCRF) of the present release from the policy decision function (PDF) and charging rules function (CRF) of Release 6, the Rx application in the present release has an own vendor specific Diameter application.

16 15 TS V8.5.0 ( ) The Rx application is defined as an IETF vendor specific Diameter application, where the vendor is 3GPP and the Application-ID for the Rx application in the present release is The vendor identifier assigned by IANA to 3GPP ( is NOTE: A route entry can have a different destination based on the application identification AVP of the message. Therefore, Diameter agents (relay, proxy, redirection, translation agents) must be configured appropriately to identify the 3GPP Rx application within the Auth-Application-Id AVP in order to create suitable routeing tables. Due to the definition of the commands used in Rx protocol, there is no possibility to skip the Auth-Application-Id AVP and use the Vendor-Specific-Application-Id AVP instead. Therefore the Rx application identification shall be included in the Auth-Application-Id AVP. With regard to the Diameter protocol defined over the Rx reference point, the PCRF acts as a Diameter server, in the sense that it is the network element that handles AF session authorization requests for a particular realm. The AF acts as the Diameter client, in the sense that is the network element requesting the authorization of resources for an AF session. 5.2 Initialization, maintenance and termination of connection and session The initialization and maintenance of the connection between each AF and PCRF pair is defined by the underlying protocol. Establishment and maintenance of connections between Diameter nodes is described in RFC 3588 [10]. After establishing the transport connection, the PCRF and the AF shall advertise the support of the Rx specific Application by including the value of the application identifier in the Auth-Application-Id AVP and the value of the 3GPP (10415) in the Vendor-Id AVP of the Vendor-Specific-Application-Id AVP contained in the Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands. The Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands are specified in the Diameter Base Protocol (RFC 3588 [10]). The termination of the Diameter user session is specified in RFC 3588 [10] in clauses 8.4 and 8.5. The description of how to use of these termination procedures in the normal cases is embedded in the procedures description (clause 4.4). 5.3 Rx specific AVPs Table describes the Diameter AVPs defined for the Rx interface protocol, their AVP Code values, types, possible flag values and whether or not the AVP may be encrypted. The Vendor-Id header of all AVPs defined in the present document shall be set to 3GPP (10415). NOTE: Most of these AVPs have already been defined in 3GPP TS [5] for Rel-6. Their definition is based on the one used for Rel-6 with some possible modifications to be applied to the Rel-7 protocols.

17 16 TS V8.5.0 ( ) Table 5.3.1: Rx specific Diameter AVPs AVP Flag rules (note 1) Attribute Name AVP Clause Value Type (note 2) Must May Should Must May Encr. Code defined not not Abort-Cause Enumerated M,V P Y Access-Network-Charging Address M,V P Y Address Access-Network-Charging Grouped M,V P Y Identifier Access-Network-Charging OctetString M,V P Y Identifier-Value Acceptable-Service-Info Grouped M,V P Y AF-Application-Identifier OctetString M,V P Y AF-Charging-Identifier OctetString M,V P Y Codec-Data OctetString M,V P Y Flow-Description IPFilterRule M,V P Y Flow-Number Unsigned32 M,V P Y Flows Grouped M,V P Y Flow-Status Enumerated M,V P Y Flow-Usage Enumerated M,V P Y Service-URN OctetString M,V P Y Specific-Action Enumerated M,V P Y Max-Requested-Bandwidth-DL Unsigned32 M,V P Y Max-Requested-Bandwidth-UL Unsigned32 M,V P Y Media-Component-Description Grouped M,V P Y Media-Component-Number Unsigned32 M,V P Y Media-Sub-Component AVP Grouped M,V P Y Media-Type Enumerated M,V P Y RR-Bandwidth Unsigned32 M,V P Y RS-Bandwidth Unsigned32 M,V P Y Service-Info-Status Enumerated M,V P Y SIP-Forking-Indication Enumerated M,V P Y NOTE 1: The AVP header bit denoted as 'M', indicates whether support of the AVP is required. The AVP header bit denoted as 'V', indicates whether the optional Vendor-ID field is present in the AVP header. For further details, see RFC 3588 [10]. NOTE 2: The value types are defined in RFC 3588 [10] Abort-Cause AVP The Abort-Cause AVP (AVP code 500) is of type Enumerated, and determines the cause of an abort session request (ASR) or of a RAR indicating a bearer release. The following values are defined: BEARER_RELEASED (0) This value is used when the bearer has been deactivated as a result from normal signalling handling. For GPRS the bearer refers to the PDP Context. INSUFFICIENT_SERVER_RESOURCES (1) This value is used to indicate that the server is overloaded and needs to abort the session. INSUFFICIENT_BEARER_RESOURCES (2) This value is used when the bearer has been deactivated due to insufficient bearer resources at a transport gateway (e.g. GGSN for GPRS) Access-Network-Charging-Address AVP The Access-Network-Charging-Address AVP (AVP code 501) is of type Address, and it indicates the IP Address of the network entity within the access network performing charging (e.g. the GGSN IP address). The Access-Network-Charging-Address AVP should not be forwarded over an inter-operator interface.

18 17 TS V8.5.0 ( ) Access-Network-Charging-Identifier AVP The Access-Network-Charging-Identifier AVP (AVP code 502) is of type Grouped, and contains a charging identifier (e.g. GCID) within the Access-Network-Charging-Identifier-Value AVP along with information about the flows transported within the corresponding bearer within the Flows AVP. If no Flows AVP is provided, the Access-Network-Charging-Identifier-Value applies for all flows within the AF session. The Access-Network-Charging-Identifier AVP can be sent from the PCRF to the AF. The AF may use this information for charging correlation with session layer. AVP Format: Access-Network-Charging-Identifier ::= < AVP Header: 502 > { Access-Network-Charging-Identifier-Value} *[ Flows ] Access-Network-Charging-Identifier-Value AVP The Access-Network-Charging-Identifier-Value AVP (AVP code 503) is of type OctetString, and contains a charging identifier (e.g. GCID) AF-Application-Identifier AVP The AF-Application-identifier AVP (AVP code 504) is of type OctetString, and it contains information that identifies the particular service that the AF service session belongs to. This information may be used by the PCRF to differentiate QoS for different application services. For example the AF-Application-Identifier may be used as additional information together with the Media-Type AVP when the QoS class for the bearer authorization at the Gx interface is selected. The AF-Application-Identifier may be used also to complete the QoS authorization with application specific default settings in the PCRF if the AF does not provide full Session-Component-Description information AF-Charging-Identifier AVP The AF-Charging-Identifier AVP (AVP code 505) is of type OctetString, contains the AF Charging Identifier that is sent by the AF. This information may be used for charging correlation with bearer layer Codec-Data AVP The Codec-Data AVP (AVP code 524) is of type OctetString. The Codec-Data AVP shall contain codec related information known at the AF. This information shall be encoded as follows: - The first line of the value of the Codec-Data AVP shall consist of either the word "uplink" or the word "downlink" (in ASCII, without quotes) followed by a new-line character. The semantics of these words are the following: - "uplink" indicates that the SDP was received from the UE and sent to the network. - "downlink" indicates that the SDP was received from the network and sent to the UE. NOTE: The first line indicates the direction of the source of the SDP used to derive the information. The majority of the information within the Codec-Data AVP indicating "downlink" describes properties, for instance receiver capabilities, of the sender of the SDP, the network in this case and is therefore applicable for IP flows in the uplink direction. Similarly, the majority of the information within the Codec-Data AVP indicating "uplink" describes properties, for instance receiver capabilities, of the sender of the SDP, the UE in this case and is therefore applicable for IP flows in the downlink direction.

19 18 TS V8.5.0 ( ) - The second line of the value of the Codec-Data AVP shall consist of either the word "offer" or the word "answer", or the word "description" (in ASCII, without quotes) followed by a new-line character. The semantics of these words are the following: - "offer" indicates that SDP lines from an SDP offer according to RFC 3264 [18] are being provisioned in the Codec-Data AVP; - "answer" indicates that SDP lines from an SDP answer according to RFC 3264 [18] are being provisioned in the Codec-Data AVP; - "description" indicates that SDP lines from a SDP session description in a scenario where the offer-answer mechanism of RFC 3264 [18] is not being applied are being provisioned in the Codec-Data AVP. For instance, SDP from an RTSP "Describe" reply may be provisioned. - The rest of the value shall consist of SDP line(s) in ASCII encoding separated by new-line characters, as specified in IETF RFC 4566 [13]. The first of these line(s) shall be an "m" line. The remaining lines shall be any available SDP "a" and "b" lines related to that "m" line. However, to avoid duplication of information, the SDP "a=sendrecv", "a=recvonly ", "a=sendonly", "a=inactive", "b:as", "b:rs" and "b:rr" lines do not need to be included Flow-Description AVP The Flow-Description AVP (AVP code 507) is of type IPFilterRule, and defines a packet filter for an IP flow with the following information: - Direction (in or out). - Source and destination IP address (possibly masked). - Protocol. - Source and destination port (The Source Port may be omitted to indicate that any source port is allowed. For the Rx interface, lists or ranges shall not be used.). NOTE: For TCP protocol, destination port may also be omitted. The IPFilterRule type shall be used with the following restrictions: - Only the Action "permit" shall be used. - No "options" shall be used. - The invert modifier "!" for addresses shall not be used. - The keyword "assigned" shall not be used. If any of these restrictions is not observed by the AF, the server shall send an error response to the AF containing the Experimental-Result-Code AVP with value FILTER_RESTRICTIONS. For the Rx interface, the Flow description AVP shall be used to describe a single IP flow. The direction "in" refers to uplink IP flows, and the direction "out" refers to downlink IP flows Flow-Number AVP The Flow-Number AVP (AVP code 509) is of type Unsigned32, and it contains the ordinal number of the IP flow(s), assigned according to the rules in Annex B.

20 19 TS V8.5.0 ( ) Flows AVP The Flows AVP (AVP code 510) is of type Grouped, and it indicates IP flows via their flow identifiers. When reporting an out of credit condition, the Final-Unit-Action AVP indicates the termination action applied to the impacted flows. If no Flow-Number AVP(s) are supplied, the Flows AVP refers to all Flows matching the media component number. AVP Format: Flows::= < AVP Header: 510 > {Media-Component-Number} *[Flow-Number] [Final-Unit-Action] Flow-Status AVP The Flow-Status AVP (AVP code 511) is of type Enumerated, and describes whether the IP flow(s) are enabled or disabled. The following values are defined: ENABLED-UPLINK (0) This value shall be used to enable associated uplink IP flow(s) and to disable associated downlink IP flow(s). ENABLED-DOWNLINK (1) This value shall be used to enable associated downlink IP flow(s) and to disable associated uplink IP flow(s). ENABLED (2) This value shall be used to enable all associated IP flow(s) in both directions. DISABLED (3) This value shall be used to disable all associated IP flow(s) in both directions. REMOVED (4) This value shall be used to remove all associated IP flow(s). The IP Filters for the associated IP flow(s) shall be removed. The associated IP flows shall not be taken into account when deriving the authorized QoS. NOTE: The interpretation of values for the RTCP flows in the Rx interface is described within the procedures in clause Flow-Usage AVP The Flow-Usage AVP (AVP code 512) is of type Enumerated, and provides information about the usage of IP Flows. The following values are defined: NO_INFORMATION (0) This value is used to indicate that no information about the usage of the IP flow is being provided. RTCP (1) This value is used to indicate that an IP flow is used to transport RTCP. AF_SIGNALLING (2) This value is used to indicate that the IP flow is used to transport AF Signalling Protocols (e.g. SIP/SDP). NO_INFORMATION is the default value. NOTE: An AF may choose not to identify RTCP flows, e.g. in order to avoid that RTCP flows are always enabled by the server.